Part of the Smithsonian complex but not officially counted as a museum, the S. Dillon Ripley Center is notable for hosting Smithsonian Associates arts, education, and entertainment programs (open both to members and to the general public; there’s usually an admission fee) and Discovery Theater children’s plays and entertainment. The center also mounts small rotating exhibits of works from various Smithsonian museums. Look for the copper-domed, hut-like structure next to the Smithsonian Castle. Its galleries and the Discovery Theater are subterranean and connect to the Freer, Sackler, and African Art museums.